Why did St. Thomas the Apostle become the patron saint of construction workers?

The legend of apostle Thomas coming to India was brought to India by Syrian Christian immigrants from West Asia in the 4th century. There is no historical record of a Christianity in India prior to this time.

St. Thomas is believed to have built The seven and a half churches in Malabar (Kerala). That is the reason the Saint has been recognised as the patron saints of construction workers.

There is a strong tradition among Syrian Christians in Kerala that St. Thomas brought Christianity to India in the 52 AD. However, there is no historical evidence to support this tradition. There is also a strong rumor spread by anti-christians that "on September 27, 2006, Pope Benedict XVI categorically denied that St. Thomas came to India. He stated that St. Thomas may have reached as far east as Northwest India (today's Pakistan). The Pope's statement is supported by the Church Fathers Origen and Clement, and the early historian of Christianity Eusibius." Though there is no evidence for this rumor too. Some of these early writers state that St. Thomas went to Edessa and Parthia, and that he established a church in Fars (Persia). But no one has contradicted the tradition that St. Thomas had come to India.